Crucible and stopper therefor



Nov. 20, 1956 A. W. BECKER ET AL CRUCIBLE AND STOPPER THEREFOR 2 Sheets-Sheet l Filed Dec. 4, 1952 f/ ff Nov. 20, 1956 A. w. BECKER ET AL 2,770,856

CRUCIBLE AND sToPPER THEREFOR Filed Deo. 4. 1952 2 Sheets-sheet 2 IN VEN TOR5. yzaaz/z @Jee/Fel' Y J/ffed M Woke?" United States Patent i CRUCIBLE AND STOPPER THEREFOR Adam W. Becker, Oxford, Ohio, and Alfred W. Woker,

St. Louis, M0., assignors to the United States of America as represented by the United States Atomic Energy Commission Application December 4, 1952, Serial No. 324,021

6 Claims. (Cl. 22-57) This invention relates to an improvement in Stoppers for crucibles and ladles.

Most ladles for molten metal are provided with a tap hole at the bottom in order to pour the metal into molds. The tap holes are provided with a stopper or plug that is designed to regulate the ilow therethrough. One difficulty encountered with the conventional stopper is the creation of a leak-proof tit in the tap hole. Accordingly, the object of this invention is to provide a tap hole that is 100% leak-proof until the metal is tapped.

This object is accomplished by a new mechanism for opening the tap hole. A leak-proof nozzle in the tap hole is provided with a cap that closes one end thereof. The cap is easily broken from the nozzle when the metal is ready to be poured. Each nozzle is replaceable after each pour.

For a better understanding of this invention reference is made to the following description and drawings in which:

Figure 1 is a vertical sectional view of a crucible provided with the novel stopper and slide member of this invention;

Figure 2 is a horizontal view, partly in section, taken on the line 2-2 of Figure 1; and

Figure 3 is a fragmentary vertical sectional view similar to Figure l, but With the crucible stopper broken so as to constitute a nozzle through which molten metal may pour from the crucible.

A crucible is generally indicated at 4 in Figure 1. It is preferably a cylindrical container composed of a refractory material, such as graphite. At the top a cover 6, which may be formed of porous carbon, is provided for heat insulation. The bottom of the crucible has a centrally disposed tap hole 8.

'I'his hole is adapted to receive a stopper 10 which forms a principal part of the present invention. The stopper is composed of a frangible refractory material, such as graphite, and has a blindbore 12 which extends from the top surface of the stopper to a point spaced from the bottom surface. The lower end of the stopper is formed as a cap 14 which is joined to a nozzle portion 16 through a reduced neck 17 which is at the closed end of the bore 12. The diameter of the reduced neck is less than the diameter of the cap 14 which is less than the diameter of the nozzle portion 16. Thus there is an external annular groove 18 at the reduced neck 17. The exteriors of the nozzle portion and the hole 8 in the crucible 4 are shaped like a truncated cone with the diameter increasing in a downward direction so that the stopper may be applied to the crucible 4 from below and the nozzle portion 16 may be firmly cemented in place in the hole 8.

Beneath the crucible 4 is an annular disk 20, which may be formed of graphite, having a slot 22 which extends across a major portion of the upper side of the disk and has an inner closed end 23. The slot 22 receives a slide member 24 which forms another important part of the present invention. 'I'he slide member is formed of a suit- Patented Nov. 20, 1956 ice able material, such as graphite, and has an inner end 25 which is engageable with the closed end 23 of the slot 22 and an outer end 26. The slide member 24 is provided with two apertures 28 and 29. The aperture 28 is disposed nearer the inner end 25 of the slide member 24 than is the aperture 29 and is provided with an annular shoulder 30 which separates a lower portion 31 of small diameter from an upper portion 32 of large diameter. The height of the upper portion 32 of the aperture 29 is greater than the height of cap 14 and width of annular groove 18. 'Ihe upper portion of the aperture 28 is larger in diameter than the cap 14 and loosely receives it in the position of Figure l, and the lower portion of the aperture 28 is smaller in diameter than the cap 14. The aperture 29 is larger in diameter than the cap 14.

Beneath the annular disk 20 is an insulator 34, which may be formed of porous carbon and which is sustained in place by means of an annular block 36, which may be formed of Zircon. As is shown in Figure l, a central bore 38 is disposed in the disk 20, the insulator 34, and block 36 which extends from the slide member 24 at the upper end to the lower end of the block 36. A perforated block 39, which may be formed of graphite, is mounted in the Zircon block 36 and is threaded into the disk 20. The block 39 protects the insulator 34 from molten metal coming from the crucible. For purposes of temperature control a thermocouple 40 is inserted into a hole 42 at one side of the crucible 4 near the lower end thereof. Suitable fastening means such as screws (not shown) may be used to fasten the disk 20 to the crucible 4.

When it is time to tap or pour the molten metal, which may be uranium (not shown), from the crucible 4, which may be in a vacuum casting furnace (not shown), the cap 14 is broken from the nozzle portion 16 of the stopper 10 by means of the slide member 24 which is driven from the position of -Figure l to that of Figure 3 by a blow applied to the outer end 26 of the slide member. When the cap 14 is severed, it drops and rests on the shoulder 30 in the aperture 28 so as to be carried out of the way by the slide member. The breaking of the cap occurs at the reduced neck 17. In the position of Figure 3 the inner end 25 of the slide member 24 engages the end 23 of the slot 22, and the bore 12 in the nozzle portion 16 is aligned with the aperture 29 through which unobstructed pouring of the metal occurs. To facilitate the pouring, the aperture 29 is made larger than the nozzle bore 12. The lower or larger end of the nozzle portion 16 is larger than the bore 12 so that the slide member 24 supports the nozzle portion 16 in the event that it may have become loosened from the crucible as a result of the blows delivered to the stopper 10 by the slide member 24 for breaking oif the cap 14.

When the pouring of the crucible 4 is completed, the crucible is separated from the disk 20, and the nozzle portion 16 is driven out. Now a new stopperv is applied to the crucible from below, the nozzle portion 16 of the new stopper seating in the hole 8 and being cemented therein.

The teachings of this invention should not be deemed to be limited to the embodiment illustrated in the drawings and described above. Many equivalent devices employing the teachings will readily be devised by persons skilled in the art. Accordingly, the present invention should be deemed to be limited only by the appended claims.

What is claimed is:

1. The combination with a crucible having a hole in its bottom, of a frangible stopper mounted in the crucible hole so as to protrude from the bottom of the crucible, the stopper having a blind bore extending from an upper end within the crucible to a region spaced from the lower end and near the bottom of the crucible and an annular notch around the body in a plane substantially normal to the bore and around the bottom of the bore, and a slide member having two spaced openings, one opening being provided with a shoulder, and means supporting the slide member adjacent the bottom of the Crucible with the pr= truding end of the stopper in the shuld'e'rop'ening whereby the slide member may be shifted to' convert the stopper to a nozzle by breaking the said'protruding end from the stopper at the annular notchand to carry said proL truding end out of the way on the shoulder of the one opening and bring the other opening into alignment with the nozzle. l p i 2. The combination with a crucible having 'a hole in it's bottom, of a stopper composed 'of a nozzle portion positioned in the hole, a cap protruding from the bottom and a frangible section between the cap and the nozzle portion, and a slide member mounted at the bottom so as to be sliiftable therealong for breaking the stopper at the frangible section and taking the cap out ofthe way to facilitate unimp'edd o'w from the crucible through the nozzle portion.

3. The combination specified in claim 2, the slide member having two openings spaced from one another in the direction of Shifting, one opening normally receiving the cap of the unbroken stopper so as to be capable of breaking off the cap by engaging the vsame upon shifting of the slide member, said one opening also having a shoulder adapted to support the cap when broken otl and carry it off, the other opening coming into alignment with the nozzle portion upon suihcient shifting of the slide member. y

4. The combination specified in claim 3, and further CII comprising a support engaging the bottom of the crucible and having a guide groove receiving the slide member, the groove having an end engaged by an end of the slide member to limit shifting thereof, thereby to determine alignment of the said other opening with the nozzle portion. I

5. In combination, a crucible stopper having a nozzle portion, al cap, and a frangible` section between the nozzle portion and the cap, and a shiftable member for breaking the cap from the nozzle portion, the shiftable member having two apertures spaced from oneanother in the direction of shifting, one aperture normally receiving the cap and being engageable with the cap upon -shifting of the shiftable member to produce breaking at the frangible section, the said one aperture having apshoulder supporting the cap when broken off to carry the cap away from the nozzle portion upon further shifting of said shiftable member, the other aperture being brought into alignment with the nozzle portion when said further shifting occurs. 6. In the combination `speciied Vin claim 5, the said other aperture having a diameter larger than the inner diameter of the nozzle portion and smaller than the outside diameter of the nozzle portion, whereby unimpeded flow may occur from the nozzle portion through said other aperture and the shiftable member at said other aperture' supports the nozzle portion if required.

References Cited in the tile of this patent UNITED STATES PATENTS n 689,585 Ijlartman Dec. 24,` 1901 1,066,753 Rast July 8, 1913 2,295,865 Rentschler Sept. l5, 1942 

